Coating composition, hard coat film, and optical disk

Abstract

One side of a substrate film 11 is coated with a coating composition containing (A) a reactive particle produced by chemically bonding an organic compound having at least one polymerizable unsaturated group in its molecule to an inorganic oxide particle, (B) a monomer or oligomer of an organic compound having at least two polymerizable unsaturated groups in its molecule, (C) an organic compound with a weight average molecular weight of at least 1500 and having at least one polymerizable unsaturated group in its molecule, and, if desired, (D) a siloxane compound having a dimethylsiloxane skeleton, and the coating composition is cured by irradiation with ionizing radiation to form a hard coat layer 12 with a thickness of 2 to 20 mum. This provides a hard coat film having adequate surface hardness and suppressed warpage.

The invention claimed is: 
     
       1. A coating composition, containing:
 (A) a reactive particle wherein an organic compound having at least one polymerizable unsaturated group in its molecule is chemically bonded to an inorganic oxide particle; 
 (B) a monomer or oligomer of an organic compound having at least two polymerizable unsaturated groups in its molecule; and 
 (C) an organic compound with a weight average molecular weight of at least 1500 and having at least one polymerizable unsaturated group in its molecule. 
 
     
     
       2. The coating composition according to  claim 1 , further containing:
 (D) a siloxane compound having a dimethylsiloxane skeleton. 
 
     
     
       3. The coating composition according to  claim 1 , wherein the organic compound (C) is an acrylate. 
     
     
       4. The coating composition according to  claim 1 , wherein the inorganic oxide particle of the reactive particle (A) is a silica particle. 
     
     
       5. The coating composition according to  claim 1 , wherein the monomer or oligomer of the organic compound (B) is a monomer or oligomer of a (meth)acrylic ester. 
     
     
       6. A hard coat film, comprising:
 a substrate film; and 
 a hard coat layer with a thickness of 2 to 20 μm, produced by coating at least one side of the substrate film with the coating composition according to any of  claims 1  to  5 , and curing the coating composition. 
 
     
     
       7. The hard coat film according to  claim 6 , wherein the substrate film is an optically transparent film composed of a polycarbonate, a cycloolefin-based polymer or a polymethyl methacrylate. 
     
     
       8. An optical disk, comprising the hard coat film according to  claim 6 .